How can I have grep not print out 'No such file or directory' errors?

If you are grepping through a git repository, I'd recommend you use git grep. You don't need to pass in -R or the path.

git grep pattern

That will show all matches from your current directory down.

Errors like that are usually sent to the "standard error" stream, which you can pipe to a file or just make disappear on most commands:

grep pattern * -R -n 2>/dev/null

I have seen that happening several times, with broken links (symlinks that point to files that do not exist), grep tries to search on the target file, which does not exist (hence the correct and accurate error message).

I normally don't bother while doing sysadmin tasks over the console, but from within scripts I do look for text files with "find", and then grep each one:

find /etc -type f -exec grep -nHi -e "widehat" {} \;

Instead of:

grep -nRHi -e "widehat" /etc

I usually don't let grep do the recursion itself. There are usually a few directories you want to skip (.git, .svn...)

You can do clever aliases with stances like that one:

find . \( -name .svn -o -name .git \) -prune -o -type f -exec grep -Hn pattern {} \;

It may seem overkill at first glance, but when you need to filter out some patterns it is quite handy.

Have you tried the -0 option in xargs? Something like this:

ls -r1 | xargs -0 grep 'some text'

Use -I in grep.

Example: grep SEARCH_ME -Irs ~/logs.

I redirect stderr to stdout and then use grep's invert-match (-v) to exclude the warning/error string that I want to hide:

grep -r <pattern> * 2>&1 | grep -v "No such file or directory"

I was getting lots of these errors running "M-x rgrep" from Emacs on Windows with /Git/usr/bin in my PATH. Apparently in that case, M-x rgrep uses "NUL" (the Windows null device) rather than "/dev/null". I fixed the issue by adding this to .emacs:

;; Prevent issues with the Windows null device (NUL)
;; when using cygwin find with rgrep.
(defadvice grep-compute-defaults (around grep-compute-defaults-advice-null-device)
  "Use cygwin's /dev/null as the null-device."
  (let ((null-device "/dev/null"))
    ad-do-it))
(ad-activate 'grep-compute-defaults)

One easy way to make grep return zero status all the time is to use || true

 → echo "Hello" | grep "This won't be found" || true

 → echo $?
   0

As you can see the output value here is 0 (Success)

Many answers, but none works, sigh

 grep "nick-banner" *.html -R -n

It does not work:

grep: *.html: No such file or directory

Problem:

This drove me bananas. I tried everything under the (Google) Sun and nothing worked with this grep which just puked repeated errors about "sysctl: reading key ..." before finally printing the match:

sudo sysctl -a | grep vm.min_free_kbytes

Solution:

Nothing worked UNTIL I had an epiphany: What if I filtered in the front rather than at the back?... Yup: that worked:

sysctl -a --ignore 2>/dev/null | grep vm.min_free_kbytes

Conclusion:

Obviously not every command will have the --ignore switch, but it's an example of how I got around the problem filtering BEFORE my grep. Don't get so blinkered you chase your tail pursuing something that won't work ;-)